I have seen some types of black plastic turn a "whitish" or "grayish" color when exposed to certain chemicals. Very often this is just on the surface and can be buffed back to the original black. I would try a little 600 wet or dry sandpaper on them before resorting to painting. I have not tried checking black widow grips but if you want to send them to me, I will give it a try. I have some carbide checking tools that should cut that plastic with no problem. If you decide to do this, PLEASE DO NOT PAINT before sending them.